I'd agree about Nirvana. I was in my early 20s when 'grunge' exploded onto the world. I thought there was nothing new or original about them at all there were tons of sh*tty bands around then that cranked up the distortion on their pedals to hide their utter lack of guitar-playing ability and had the same sort of gutteral (or whining) vocals in lieu of any singing ability.

They had one fairly catchy song that grabbed the zeitgeist at the time (Smells like Teen Spirit) that was tolerable, the rest was utter crap.

That cover of the Bowie song was horrible but it certainly revealed what a gawd-awful singer Cobain was - over-emoted, pronounced certain words strangely, cracked his voice too much etc.

That, and their lyrics are atrocious.

Having said that, I'd have to include Pearl Jam. Again, one tolerable song - Jeremy - and the rest were crap (though at least unlike Cobain the guy could sing).